<template>
  <div id="app" class="score-case">
    <div class="table">
      <table>
        <thead>
          <tr>
            <th>编号</th>
            <th>科目</th>
            <th>成绩</th>
            <th>操作</th>
          </tr>
        </thead>
        <tbody v-if="list.length > 0">
          <tr v-for="(item,index) in list" :key="index">
            <td>{{item.id}}</td>
            <td>{{item.subject}}</td>
            <td :class="{red:item.score < 60}">{{item.score}}</td>
            <td>
              <a href="#" @click="remove(item.id)">删除</a>
            </td>
          </tr>
        </tbody>
        <tbody v-else>
          <tr>
            <td colspan="5">
              <span class="none">暂无数据</span>
            </td>
          </tr>
        </tbody>

        <tfoot>
          <tr>
            <td colspan="5">
              <span>总分：{{totalPoints}}</span>
              <span style="margin-left: 50px">平均分：{{averageScore}}</span>
            </td>
          </tr>
        </tfoot>
      </table>
    </div>
    <div class="form">
      <div class="form-item">
        <div class="label">科目：</div>
        <div class="input">
          <input v-Myfocus v-borderColor="BorderColor" type="text" v-model.trim="subject" @keyup.enter="add" placeholder="请输入科目">
        </div>
      </div>
      <div class="form-item">
        <div class="label">分数：</div>
        <div class="input">
          <input class="focusInput" type="text" v-model.number="score" @keyup.enter="add" placeholder="请输入分数">
        </div>
      </div>
      <div class="form-item">
        <div class="label"></div>
        <div class="input">
          <button class="submit" @click="add" >添加</button>
        </div>
      </div>
    </div>
  </div>
</template>
<script>
export default {
  name: "AchievementCase",
  //局部自定义指令
  directives:{
    "borderColor":{
      inserted(el,binding){
        el.style.borderColor = binding.value
      },
      //实现数据驱动视图改变
      update(el,binding){
        el.style.borderColor = binding.value
      }
    }
  },
  data() {
    return {
      list: [
        
      ],
      subject: "",
      score: "",
      BorderColor:'#58bc58'
    };
  },
  computed:{
      totalPoints(){
        //   写法一：
        return this.list.reduce((sum,item)=> sum +item.score, 0)
        //   写法二：
        // return this.list.reduce((sum,item)=>{
        //     return sum + item.score
        // },0)
      },
      averageScore(){
          if (this.list.length === 0){
              return 0 
          }
          return (this.totalPoints / this.list.length).toFixed(2)
      }    
  },
  methods:{
      remove(id){
         this.list = this.list.filter((item)=> item.id !== id)
      },
      add(){
          if(typeof this.score !== 'number' || this.subject == ''){
              alert('请输入数字/或勿空')
          }else{
              this.list.push({id:this.list.length+1,subject:this.subject,score:this.score})
          }
      }
  }
};
</script>
<style scoped>
.score-case {
  width: 1000px;
  margin: 50px auto;
  display: flex;
}
.score-case .table {
  flex: 4;
}
.score-case .table table {
  width: 100%;
  border-spacing: 0;
  border-top: 1px solid #ccc;
  border-left: 1px solid #ccc;
}
.score-case .table table th {
  background: #f5f5f5;
}
.score-case .table table tr:hover td {
  background: #f5f5f5;
}
.score-case .table table td,
.score-case .table table th {
  border-bottom: 1px solid #ccc;
  border-right: 1px solid #ccc;
  text-align: center;
  padding: 10px;
}
.score-case .table table td.red,
.score-case .table table th.red {
  color: red;
}
.score-case .table .none {
  height: 100px;
  line-height: 100px;
  color: #999;
}
.score-case .form {
  flex: 1;
  padding: 20px;
}
.score-case .form .form-item {
  display: flex;
  margin-bottom: 20px;
  align-items: center;
}
.score-case .form .form-item .label {
  width: 60px;
  text-align: right;
  font-size: 14px;
}
.score-case .form .form-item .input {
  flex: 1;
}
.score-case .form .form-item input,
.score-case .form .form-item select {
  appearance: none;
  outline: none;
  border: 1px solid #ccc;
  width: 200px;
  height: 40px;
  box-sizing: border-box;
  padding: 10px;
  color: #666;
}
.score-case .form .form-item input::placeholder {
  color: #666;
}
.score-case .form .form-item .cancel,
.score-case .form .form-item .submit {
  appearance: none;
  outline: none;
  border: 1px solid #ccc;
  border-radius: 4px;
  padding: 4px 10px;
  margin-right: 10px;
  font-size: 12px;
  background: #ccc;
}
.score-case .form .form-item .submit {
  border-color: #069;
  background: #069;
  color: #fff;
}
.focusInput:focus{
  font-size: 12px;
  border-color:#58bc58;
}
</style>

